He completed the 2005 season in Tacoma and pitched in seven spring training games with the big league squad in Arizona before opening 2006 back in Tacoma. His spring training performance and 4–0 record and 1.38 ERA as the Rainiers' closer caught the eye of Mariners manager Mike Hargrove.

Green made it to the big leagues when the Seattle Mariners called him up on April 29, 2006, to replace reliever Julio Mateo. When Mateo was activated on May 20, it was thought that Green would return to Triple-A Tacoma, but the Mariners opted to instead send down pitcher Emiliano Fruto. He made his first Major League appearance on May 2 against the Minnesota Twins.

Green was a solid contributor out of the bullpen in 2007, logging 68 innings out of the bullpen with a 3.84 ERA in 64 games for the Mariners.

In 2008, Green dominated before the All-Star break, with a 2.72 ERA, but after the All-Star break, Green had an 8.65 ERA. He would finish the season with a 4.67 ERA in a career high 79 innings.

On December 10, 2008, Green was sent to the New York Mets as a part of a 12-player, 3-team trade that sent reliever J.J. Putz to New York.[1]

Despite hype for Green, he struggled in his first year and was eventually demoted to the Mets minor league, AAA affiliate. He would eventually make it back and provided the Mets with 79 relief appearances despite having an ERA of 4.52.

In early April 2010, Green was given the final bullpen spot but he was put on the DL with a broken rib. It was reported that Green has recovered from the injury but was still rehabing in the minors. Green returned to the Mets on September 6, 2010, as part of the Mets September callups. On December 3, 2010, the Mets non-tendered Green, making him a free agent.

Green signed a minor league contract with the Texas Rangers on January 23, 2012. He also received an invitation to spring training. Green allowed 21 runs in 27.1 innings at the AAA level for the Rangers, he was subsequently released.